Abstract:

In order to explore the method of improving the germination rate of Gynostemma pentaphyllum seeds，we investigated the effects of different factors，namely，illumination and temperature，hormone，storage，low temperature stratification and short-term low temperature.The results showed that the optimal germination temperature ranged from 15℃ to 25 ℃；illumination raised the germination rate，with the highest germination rate（31.54±2.04）% at the optimum temperature of 20  ℃. It was found that Cytokinins，such as 6-BA and zeatin，had no effect on the promotion of the germination，and Gibberellin，like GA3，had almost no impact,but GA4 promoted the germination to （54.00±2.65）%.At 18  ℃,Gynostemma pentaphyllum seeds were stored for 30，90，and 180 days.The results showed that appropriate storage time was conducive to break the dormancy mechanism of Gynostemma pentaphyllum seed，but when the storage time was too long，the germination rate declined rapidly，or even to zero.The statistics of low temperature stratification processing showed that the effect of low temperature stratification was not obvious.Under low temperature stratification for 90 days，the highest germination rate was only（34.26±3.21）%.By short-term low temperature treatment，it was found that short-term low temperature (9 days of moist storage at 5，10，15  ℃) increased the germination rate to （73.06±2.12）%，（83.14±3.25）% and （72.13±3.52）%.Comparison of storage treatment and post-storage short-term low temperature treatment showed that，with the increase in storage time，the germination rate decreased rapidly，while short-term low temperature treatment still promoted the germination of long-stored seeds.

Key words: Gynostemma pentaphyllum；germination rate；low temperature stratification；illumination；short-term low temperature, storage time；plant hormone